Structural polypeptides of the enteropathogenic bovine coronavirus strain LY-138

Abstract

The bovine coronavirus strain LY-138 was purified by differential as well as velocity and isopycnic centrifugation in sucrose or CsCl gradients. The substrate for purification was contents of the small intestine of experimentally inoculated calves. This strain is highly enteropathogenic, but it could not yet be propagated in cultured cells. Intact virions had a density of 1.245 g/cm³ in CsCl and 1.185 g/cm³ in sucrose. A spherical core-like structure with an average diameter of 82 nm remaining after treatment with chloroform had a density of 1.299 g/cm³ in CsCl and 1.201 g/cm³ in sucrose. Seven distinct bands of polypeptides and 4 shoulders were detected after electrophoresis of SDS-solubilized virions in polyacrylamide gels. The approximate molecular weights ranged from 110,000 to 36,000. Four of the bands gave a PAS positive reaction. These 4 glycoproteins and an additional protein with an approximate molecular weight of 70,000 were removed by chloroform treatment. The remaining core-like structure contained the 2 polypeptides VP3 and VP7.